Belt-like material-feeding apparatus and method of operating the same

ABSTRACT

A belt-like material-feeding apparatus for continuously feeding a belt-like material to a treating unit, comprises a splicing unit which splices a second belt-like material to a first belt-like material being fed to the treating unit to thereby switch the belt-like material being fed to the treating unit from the first belt-like material into the second belt-like material, an accumulating unit which is arranged between the splicing unit and the treating unit and is capable of temporarily accumulating the belt-like material, and a control unit which, prior to the splicing operation of the splicing unit, increases the amount of accumulation of the belt-like material to be larger than the amount of accumulation of the belt-like material during the steady operation and, during the splicing operation, releases the belt-like material from the accumulating unit to decrease the amount of accumulation of the belt-like material.

TECHNICAL FIELD

The present invention relates to a belt-like material-feeding apparatusand a method of operating the same.

BACKGROUND ART

A belt-like material-feeding apparatus for continuously feeding abelt-like material to a treating unit, including a splicing unit whichsplices a second belt-like material to a first belt-like material beingfed to the treating unit to thereby switch the belt-like material beingfed to the treating unit from the first belt-like material into thesecond belt-like material, and an accumulating unit which is arrangedbetween the splicing unit and the treating unit and is capable oftemporarily accumulating the belt-like material, in which, when thesplicing operation of the splicing unit is completed, the amount ofaccumulation of the belt-like material is increased up to a maximumamount of accumulation of the accumulating unit and then a steadyoperation is conducted and, during the splicing operation, the belt-likematerial is released from the accumulating unit to decrease the amountof accumulation of the belt-like material (see PLT 1) has been known.This enables the belt-like material to be released from the accumulatingunit during the splicing operation and, therefore, enables the belt-likematerial to be continuously fed.

The accumulating unit includes winding rolls and dancer rolls roundwhich the belt-like material is alternately wrapped. The amount ofaccumulation of the belt-like material increases with an increase in thedistance between the winding rolls and the dancer rolls and decreaseswith a decease in the distance between the winding rolls and the dancerrolls.

CITATION LIST Patent Literature

PLT 1: Japanese Unexamined Patent Publication No. 7-137899

SUMMARY OF INVENTION Technical Problem

The above belt-like material-feeding apparatus is operated steadily in acondition where the belt-like material is accumulated in large amountsin the accumulating unit. In the condition where the belt-like materialis accumulated in large amounts, however, the distance is increasedbetween the winding rolls and the dancer rolls. Thus, the belt-likematerial traveling through the splicing unit may lose stability i.e.,the belt-like material may meander or may be wrinkled. When thebelt-like material is comprised of a nonwoven fabric, particularly,meandering becomes a problem. When the belt-like material is comprisedof a film, on the other hand, wrinkling becomes a problem, particularly.

Solution to Problem

According to one aspect of the invention, there is provided a belt-likematerial-feeding apparatus for continuously feeding a belt-like materialto a treating unit, comprising: a splicing unit which splices a secondbelt-like material to a first belt-like material being fed to thetreating unit to thereby switch the belt-like material being fed to thetreating unit from the first belt-like material into the secondbelt-like material; an accumulating unit which is arranged between thesplicing unit and the treating unit and is capable of temporarilyaccumulating the belt-like material; and a control unit which, prior tothe splicing operation, of the splicing unit, increases the amount ofaccumulation of the belt-like material to be larger than the amount ofaccumulation of the belt-like material during the steady operation and,during the splicing operation, releases the belt-like material from theaccumulating unit to decrease the amount of accumulation of thebelt-like material.

According to another aspect of the invention, further, there is provideda method of operating a belt-like material-feeding apparatus forcontinuously feeding a belt-like material to a treating unit, theapparatus comprising: a splicing unit which splices a second belt-likematerial to a first belt-like material being fed to the treating unit tothereby switch the belt-like material being fed to the treating unitfrom the first belt-like material into the second belt-like material;and an accumulating unit which is arranged between the splicing unit andthe treating unit and is capable of temporarily accumulating thebelt-like material, wherein, prior to the splicing operation of thesplicing unit, the amount of accumulation of the belt-like material isincreased to be larger than the amount of accumulation of the belt-likematerial during the steady operation and, during the splicing operation,the belt-like material is released from the accumulating unit todecrease the amount of accumulation of the belt-like material.

Advantageous Effects of Invention

The belt-like material can be stably fed during the steady operationwhile maintaining continued feeding of the belt-like material during thesplicing operation.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a general view of a belt-like material-feeding apparatus;

FIG. 2 is a view illustrating the operation of the belt-likematerial-feeding apparatus;

FIG. 3 is a view illustrating the operation of the belt-likematerial-feeding apparatus;

FIG. 4 is a view illustrating the operation of the belt-likematerial-feeding apparatus;

FIG. 5 is a time chart of the amount of accumulation of the belt-likematerial;

FIG. 6 is a time chart of the amount of accumulation of the belt-likematerial according to another embodiment; and

FIG. 7 is a flowchart for executing a control for feeding a belt-likematerial.

DESCRIPTION OF EMBODIMENTS

FIG. 1 shows a case where the present invention is applied to abelt-like material-feeding apparatus in an apparatus for producingabsorptive materials. Namely, the apparatus for producing absorptivematerials comprises a plurality of treating units, and the belt-likematerial-feeding apparatus feeds the belt-like material to thesetreating units. The treating units subject the belt-like material tosuch treatments as cutting, embossing and shaping including folding, aswell as to such treatments as application of an adhesive, assemblingwith another member and the like. The absorptive material may be, forexample, a sanitary napkin, a panty liner, an incontinence pad or adiaper. Further, the belt-like material is a member forming theabsorptive material, and is comprised of, for example, tissue paper, anonwoven fabric or a plastic film such as of polyethylene. The belt-likematerial may be untreated or treated. The present invention can be,further, applied to the belt-like material-feeding apparatus for anyother use.

Referring to FIG. 1, a belt-like material-feeding apparatus 1 forcontinuously feeding a belt-like material S to a treating unit Tcomprises a delivery unit 2 for delivering the belt-like material S tothe treating unit T. The delivery unit 2 comprises a plurality ofsub-units, such as a left delivery unit 2L and a right delivery unit 2R.The left delivery unit 2L and the right delivery unit 2R, respectively,comprises belt-like material sources in the form of rolls 4L, 4R ofbelt-like materials rotatably held by hangers 3L and 3R, and deliverybelts 5L and 5R for unwinding the belt-like materials from the rolls 4Land 4R and for delivering them. The delivery belts 5L and 5R are,respectively, wrapped round the drive rolls and the idle rolls and isdriven to rotate, and the positions thereof can be so varied as to stayin contact with the outer circumferential surfaces of the rolls 4L, 4Ror not to come in contact therewith. The belt-like material sources mayassume a form other than the rolls. The belt-like material from the leftdelivery unit 2L and the belt-like material from the right delivery unit2R may be the same or different. Further, the belt-like materials may beunwound and delivered from the rolls 4L and 4R by rotating the hangers3L and 3R. This makes it possible to omit the delivery belts 5L and 5R.

When the delivery belts 5L and 5R are contacted with the outercircumferential surfaces of the rolls 4L and 4R to rotate them, thebelt-like materials are unwound from the rolls 4L and 4R and aredelivered. When the rotations of the delivery belts 5L and 5R arestopped or the delivery belts 5L and 5R are separated away from theouter circumferential surfaces of the rolls 4L and 4R, on the otherhand, delivery of the belt-like materials is stopped. Either the leftdelivery unit 2L or the right delivery unit 2R is operated and,therefore, the belt-like material is delivered from either one of them.

The belt-like material-feeding apparatus 1 further comprises a splicingunit 6 which splices a second belt-like material to the first belt-likematerial being fed from the delivery unit 2 to the treating unit T tothereby switch the belt-like material S being fed to the treating unit Tfrom the first belt-like material into the second belt-like material.Namely, when the belt-like material is being fed to the treating unit Tfrom the left delivery unit 2L, the belt-like material from the rightdelivery unit 2R is spliced to the belt-like material that is being fedto thereby switch the belt-like material being fed to the treating unitT into the belt-like material from the right delivery unit 2R. Or whenthe belt-like material from the right feed unit 2R is being fed to thetreating unit T, the belt-like material from the left delivery unit 2Lis spliced to the belt-like material being fed to thereby switch thebelt-like material being fed to the treating unit T into the belt-likematerial from the left delivery unit 2L. The splicing unit 6 comprises,for example, pushers 7L, 7R and a stationary member 8.

In the case where the belt-like material is comprised of a thermoplasticresin, the splicing unit can be comprised of a welding type includingheaters at the tips of the pushers 7L and 7R. That is, the belt-likematerials from the left delivery unit 2L and the right delivery unit 2Rare arranged being overlapped between the pusher 7L, 7R and thestationary member 8, and are pushed by the pusher 7L, 7R onto thestationary member 8 and the heater is energized. As a result, thebelt-like materials are welded to each other while being held, and thusare spliced together. At this moment, further, the belt-like materialbeing fed is weld-cut. When the splicing operation is not conducted, onthe other hand, the pushers 7L and 7R stay away from the stationarymember 8 and, therefore, the belt-like materials pass through thesplicing unit 6.

Alternatively, the two belt-like materials may be spliced together byadhesion. In this case, the belt-like materials may be comprised of athermoplastic resin or a non-thermoplastic resin. There can be, further,provided a cutting tool for cutting the belt-like materials being fed.

The belt-like material-feeding apparatus 1, further, comprises anaccumulating unit 9 which is arranged between the splicing unit 6 andthe treating unit T and is capable of temporarily accumulating thebelt-like materials. The accumulating unit 9 comprises stationarywinding rolls 10 and dancer rolls 11 capable of moving in a verticaldirection, and the belt-like materials are alternately wrapped round thewinding rolls 10 and the dancer rolls 11.

When the tension of the belt-like materials decreases in theaccumulating unit 9, the dancer rolls 11 descend due to their ownweights and the vertical position of the dancer rolls 11 becomes lower.As a result, the distance increases between the winding rolls 10 and thedancer rolls 11, and an amount of the belt-like materials accumulated inthe accumulating unit 9 increases. When the tension of the belt-likematerials increases, on the other hand, the dancer rolls 11 ascend andthe vertical position of the dancer rolls 11 becomes higher. As aresult, the distance decreases between the winding rolls 10 and thedancer rolls 11, and the amount of accumulation of the belt-likematerials decreases. Thus, the vertical position of the dancer rolls 11represents the amount of the belt-like materials accumulated in theaccumulating unit 9. A weight may be added to the dancer rolls 11.Alternatively, the vertical position of the dancer rolls 11 may becontrolled by using an actuator such as a servo motor.

In this case, the amount of the belt-like materials accumulated in theaccumulating unit 9 is controlled depending upon the deliverying speedof the belt-like materials from the delivery unit 2. Namely, when thedelivering speed of the delivery belts 5L and 5R is increased, thetension of the belt-like materials decreases and, therefore, the amountof accumulation of the belt-like materials increases. On the other hand,when the delivering speed of the delivery belts 5L and 5R is decreased,the tension of the belt-like materials increases and, therefore, theamount of accumulation of the belt-like materials decreases.

Referring to FIG. 1, further, between the accumulating unit 9 and thetreating unit T, there are provided a taking roll 12 which takes thebelt-like materials from the accumulating unit 9 and feeds them to thetreating unit T, and a tension adjuster 13 for adjusting the tension ofthe belt-like materials. The feeding speed of the taking toll 12 is insynchronism with the rate of production speed or the delivery speed ofthe apparatus for producing absorptive materials. Therefore, the takingroll 12 feeds the belt-like materials to the treating unit T at asubstantially constant speed.

In FIG. 1, reference numeral 14 denotes idle rolls.

A controller 15 is comprised of a computer including, for example, a CPU(microprocessor), memory, input ports and output ports. The deliveryunit 2 is provided with rotational speed sensors 16L and 16R fordetecting the rotational speeds of the rolls 4L and 4R, and tail endsensors 17L and 17R such as cameras for detecting the passage of tailends of the belt-like materials. Further, the dancer rolls 11 areprovided with a position sensor 18 for detecting the vertical positionof the dancer rolls 11. The sensors 16L, 16R, 17L and 17R are connectedto the input ports of the controller 15, and the output signals from thesensors are input to the controller 15. The feed belts 5L and 5R,pushers 7L and 7R and taking roller 12, on the other hand, are connectedto the output ports of the controller 15, and are controlled based onthe output signals from the controller 15.

FIG. 1 illustrates a condition where the belt-like material-feedingapparatus 1 is in a steady operation. In this example, the belt-likematerial S is fed from the left delivery unit 2L. The belt-like materialis, then, fed to the treating unit T through the splicing unit 6 and theaccumulating unit 9.

In this case, the dancer rolls 11 are maintained at nearly the highestposition P, i.e., the amount of the belt-like material accumulated inthe accumulating unit 9 is maintained at nearly a minimum amount.Specifically, the delivering speed of the delivery belt 5L is feedbackcontrolled so that the dancer rolls 11 detected by the position sensor18 are maintained at the highest position P.

Next, when the remaining amount of the belt-like material of the roll 4Lin the left delivery unit 2L becomes smaller than a predeterminedlower-limit amount, an operation for accumulating the belt-like materialis conducted. Namely, the delivering speed of the left delivery unit 2Lis increased and is maintained increased. As a result, the verticalposition of the dancer rolls 11 gradually decreases, i.e., the amount ofthe belt-like material accumulated in the accumulating unit 9 increasesgradually.

The remaining amounts of the belt-like materials of the rolls 4L and 4Rcan be calculated based upon the rotational speeds of the rolls 4L and4R detected by the rotational speed sensors 16L and 16R. Alternatively,whether the remaining amounts of the belt-like materials of the rolls 4Land 4R are smaller than the lower-limit amount may be judged based uponthe outer diameters of the rolls 4L and 4R which can be determined byphotoelectric tube sensors, proximity sensors, limit switches orcameras. The lower-limit value, on the other hand, may be a constantvalue or may be set depending on the rate of production of the apparatusfor producing absorptive materials. This makes it possible to decreasethe effect of variation in the thickness of the belt-like materials inthe rolls 4L and 4R.

Next, as shown in FIG. 2, when the dancer rolls 11 arrive at the lowestposition, i.e., the amount of accumulation of the belt-like materialincreases up to the maximum amount of accumulation of the accumulatingunit 9, and when the passage of the tail end of the belt-like material Sis detected by the end sensor 17L, then the rotation of the deliverybelt 5L is stopped. Therefore, the increment of the amount ofaccumulation of the belt-like material is stopped.

Next, the splicing operation by the splicing unit 6 starts. That is, asshown in FIG. 3, the pusher 7L is activated to splice the tail end partof the belt-like material from the left delivery unit 2L to the leadingend part of the belt-like material from the right delivery unit 2R. Theleading end part of the belt-like material from the right delivery unit2R has been arranged on the stationary member 8 in advance by, forexample, an operator.

While the splicing operation is being conducted in this manner, thebelt-like material accumulated in the accumulating unit 9 iscontinuously released to the treating unit T by the taking roll 12 and,thus, the belt-like material is continuously fed to the treating unit T.Therefore, the splicing operation is conducted without stopping theapparatus for producing absorptive materials. In the accumulating unit9, on the other hand, the dancer rolls 11 gradually ascend and theamount of accumulation of the belt-like material gradually decreases.

Next, as shown in FIG. 4, when the dancer rolls 11 return back to thehighest position, i.e., the amount of accumulation of the belt-likematerial returns back to the minimum amount of accumulation, then thesplicing operation is completed. That is, the pusher 7L returns back toits initial position, and the belt-like material is released. At thismoment, further, the delivery belt 5R is contacted with thecircumferential surface of the roll 4R and is driven to rotate. As aresult, the delivery of the belt-like material from the right deliveryunit 2R starts.

While the belt-like material is being delivered from the right deliveryunit 2R, a new roll 4L is set to the hanger 3L in the left delivery unit2L, and the leading end of the new roll 4L is arranged on the stationarymember 8.

Next, when the remaining amount of the belt-like material of the roll 4Rbecomes small in the right delivery unit 2R, the splicing operation isconducted again and the belt-like material is fed from the roll 4L ofthe left delivery unit 2L.

Namely, referring to FIG. 5, during the steady operation designated atSTD, the amount of accumulation Q of the belt-like material in theaccumulating unit 9 is maintained at a minimum amount of accumulationQm. Next, when the remaining amount of the belt-like material becomessmaller than the lower-limit amount as designated at X in FIG. 5, theamount of accumulation of the belt-like material is increased in asubsequent period ACM. Next, when the amount of accumulation Q of thebelt-like material increases to a maximum amount of accumulation QM asdesignated at Y in FIG. 5, the amount of accumulation Q of the belt-likematerial is decreased in a subsequent period SPL and, at this time, thesplicing operation is conducted. Next, when the amount of accumulation Qof the belt-like material decreases down to the minimum amount ofaccumulation Qm as designated at Z in FIG. 5, the steady operation STDis resumed.

This stabilizes the behavior of the belt-like material traveling throughthe accumulating unit 9 during the steady operation. Therefore,meandering of or formation of wrinkles in the belt-like material issuppressed during the steady operation.

Further, in case the apparatus for producing absorptive articles stopsdue to some reasons and thus the taking roll 12 also stops, despite therotation of the delivery belts 5L and 5R are stopped, the rolls 4L and4R may continue to rotate due to inertia to deliver the belt-likematerial excessively, slack may occur in the belt-like material.However, the excess belt-like material is accumulated in theaccumulating unit 9, preventing the belt-like material from beingslackened. Therefore, the operation of the apparatus for producingabsorptive articles can be easily resumed.

Accordingly, generally speaking, prior to the splicing operation of thesplicing unit, the amount of accumulation of the belt-like material isincreased to be larger than the amount of accumulation of the belt-likematerial during the steady operation and, during the splicing operation,the belt-like material is released from the accumulating unit todecrease the amount of accumulation of the belt-like material.

The amount of accumulation QSTD of the belt-like material during thesteady operation may be arbitrarily set as long as it is not the maximumamount of accumulation QM. Further, the amount of accumulation QSPL atthe start of the splicing operation may be arbitrarily set as long as itis not the minimum amount of accumulation Qm. From the standpoint ofstability in the behavior of the belt-like material during the steadyoperation and the period for the splicing operation, however, it isdesired that the amount of accumulation QSTD of the belt-like materialduring the steady operation is set to be the minimum amount ofaccumulation Qm and the amount of accumulation QSPL of the melt-likematerial at the start of the splicing operation is set to be the maximumamount of accumulation QM.

On the other hand, the ratio (QSPL/QSTD) of the amount of accumulationQSTD of the belt-like material during the steady operation and theamount of accumulation QSPL of the belt-like material at the start ofthe splicing operation can be set to be, for example, 20 to 200. Theamount of accumulation of the belt-like material can be expressed by aconveyed distance of the belt-like material in the accumulating unit 9.

In order to suppress a quick change in the amount of accumulation Q ofthe belt-like material, as shown in FIG. 6, the delivery belts 5L and 5Rcan be so controlled that the delivering speed gradually increases orgradually decreases. This decreases the load exerted on the deliverybelts 5L and 5R, and suppresses the belt-like material from slackeningor stretching in the accumulating unit 9.

FIG. 7 illustrates a routine for a belt-like material feed controlaccording to an embodiment of the present invention.

Referring to FIG. 7, in step 100, it is judged if a remaining amount QRof the roll 4L, 4R that is feeding the belt-like material is smallerthan the lower-limit amount LL. If QL≧LL, the routine proceeds to step101 to conduct the steady operation. If QL<LL, on the other hand, theroutine proceeds to step 102 where the operation of accumulation of thebelt-like material is conducted. In subsequent step 103, it is judged ifthe amount of accumulation Q of the belt-like material has reached themaximum amount of accumulation QM of the accumulating unit 9 and thepassage of the tail end of the belt-like material being fed is detected.If Q<QM or if the passage of the tail end of the belt-like material hasnot yet been detected, step 103 is repeated. If Q=QM and if the passageof the tail end of the belt-like material is detected, the routineproceeds to step 104 where the delivering operation by the deliverybelts 5L, 5R is stopped. In subsequent step 105, the splicing operationis conducted by the splicing unit 6. In next step 106, it is judged ifthe amount of accumulation Q of the belt-like material has decreaseddown to the minimum amount of accumulation Qm. If Q>Qm, step 106 isrepeated. If Q=Qm, the routine proceeds to step 107 where the splicingoperation is completed. In next step 108, the delivering operation bythe delivery belts 5L, 5R starts.

In the above embodiment, it is judged if the amount of accumulation Q ofthe belt-like material is the maximum amount of accumulation Qm or theminimum amount of accumulation Qm based on the detected verticalposition of the dancer rolls 11. Alternatively, it is also allowable tojudge if the dancer rolls 11 are at the highest position or the lowestposition by using a photoelectric tube sensor, proximity sensor or limitswitch, and judge if the amount of accumulation Q of the belt-likematerial is the maximum amount of accumulation QM or the minimum amountof accumulation Qm based on the above judged result.

REFERENCE SIGNS LIST

1 belt-like material-feeding apparatus

2 delivery unit

6 splicing unit

9 accumulating unit

10 winding rolls

11 dancer rolls

15 controller

T treating unit

1. A belt-like material-feeding apparatus for continuously feeding abelt-like material to a treating unit, comprising: a splicing unit whichsplices a second belt-like material to a first belt-like material beingfed to the treating unit to thereby switch the belt-like material beingfed to the treating unit from the first belt-like material into thesecond belt-like material; an accumulating unit which is arrangedbetween the splicing unit and the treating unit and is capable oftemporarily accumulating the belt-like material; and a control unitwhich, prior to the splicing operation of the splicing unit, increasesthe amount of accumulation of the belt-like material to be larger thanthe amount of accumulation of the belt-like material during the steadyoperation and, during the splicing operation, releases the belt-likematerial from the accumulating unit to decrease the amount ofaccumulation of the belt-like material.
 2. The belt-likematerial-feeding apparatus according to claim 1, wherein the amount ofaccumulation of the belt-like material during the steady operation is aminimum amount of accumulation of the accumulating unit.
 3. Thebelt-like material-feeding apparatus according to claim 1, wherein thecontrol unit increases the amount of accumulation of the belt-likematerial up to a maximum amount of accumulation of the accumulatingunit.
 4. The belt-like material-feeding apparatus according to claim 1,wherein the accumulating unit comprises winding rolls and dancer rollsround which the belt-like material is wrapped, and the control unitincreases the distance between the winding rolls and the dancer rolls toincrease the amount of accumulation of the belt-like material anddecreases the distance between the winding rolls and the dancer rolls todecrease the amount of accumulation of the belt-like material.
 5. Thebelt-like material-feeding apparatus according to claim 1, wherein whenthe amount of accumulation of the belt-like material has decreased downto the amount of accumulation of the belt-like material during thesteady state, the second belt-like material is delivered to theaccumulating unit.
 6. A method of operating a belt-like material-feedingapparatus for continuously feeding a belt-like material to a treatingunit, the apparatus comprising: a splicing unit which splices a secondbelt-like material to a first belt-like material being fed to thetreating unit to thereby switch the belt-like material being fed to thetreating unit from the first belt-like material into the secondbelt-like material; and an accumulating unit which is arranged betweenthe splicing unit and the treating unit and is capable of temporarilyaccumulating the belt-like material, wherein, prior to the splicingoperation of the splicing unit, the amount of accumulation of thebelt-like material is increased to be larger than the amount ofaccumulation of the belt-like material during the steady operation and,during the splicing operation, the belt-like material is released fromthe accumulating unit to decrease the amount of accumulation of thebelt-like material.